I'm sorry, I'm not technically allowed to give critiques on 250 boxes since I haven't posted my own to the website due to personal problems, if all goes well I might give you a proper critique in a few days/about a week if you don't mind the wait! But I can point out some things I noticed really quickly to you

While I believe you understood the point of the challenge, you did a lot of 1 point and 2 point perspective boxes, which is not really encouraged since we should stick with 3 point perspective boxes to learn how to rotate them freely in space, which more often than not will be in 3 point perspective.

You had trouble checking for your convergences even to the end, don't forget that those follow your initial Y, imagine that each line on your Y has a little arrow head, that's where you should extend your mark towards.

You gave up on some boxes, don't do that, if you give up on a box you're giving up on learning. There's a lot we can learn even from a "terrible" box, and it also goes against DAB's principle of confidence and pushing through even if you've made some mistakes.

I can also notice some little dots you made in a few boxes, and redone lines, almost as if you were trying to correct or see how the box should actually be constructed which is also not how we check for mistakes, instead of doing that when you try to draw a similar box look back on your older ones and try to see how much more you should push your lines so they converge better, you'll gain more experience that way

That's all I can really point out